Machine for grinding of workpieces

ABSTRACT

Batches of identical turnplates or analogous metallic workpieces are ground in an automatic machine wherein a pusher evacuates workpieces from a magazine and delivers them into the receptacle of a transfer unit which changes the orientation of such workpieces and places them between two pins of a clamping unit. The latter is mounted on a carriage which is reciprocable along a supporting table and moves the workpieces against the active surface of a cupped grinding wheel.

United States Patent 119 Amrhein et al.

[ 51 Mar. 27, 1973 MACHINE FOR GRINDING OF WORKPIECES Heinz G. Amrhein, Buderich; HermanfStander, Dusseldorf; Heinz Rosenow, Osterath, all of Germany Filed: May 12, 1970 Appl. No.: 36,582

Inventors:

ForeignApplication Priority Data May 13, 1969 Germany .LP 19 24 315.3

Us. c1... ..51/56, 51/127, 51/215 CP, 1 51/215 H 1m. (:1. ..B24b 7/00, B24b 5/00 Field of Search, 051/56, 125.5, 127, 2 15 CP, 51/215 H; 204/143 G References Cited UNITED STATES PATENTS 916,650 3/1909 Baken; ..51/56 1,332,248 3/1920 Doane ..5l/215 H X 2,600,432 6/1952 Sanders ..5 H127 2,773,332 12/1956 Buchman et al. ....51/215 H X 2,796,703 6/1957 Bushey et a] ....51/215 H X 2,805,197 9/1957 Thibault et al. ..204/143 G Primary Examiner-Lester M. Swingle Attorney-Michael S. Striker ABSTRACT Batches of identical tumplates or analogous metallic workpieces are ground in an automatic machine wherein a pusher evacuates workpieces from a magazine and delivers them into the receptacle of a transfer unit which changes the orientation of such workpieces and places them between two pins of a clamping unit. The latter is mounted on a carriage which is reciprocable along a supporting .table and moves the workpieces against the active surface of a cupped grinding wheel.

41 Claims, 39 Drawing Figures #9 ill PATENTEDHARZYISYS SHEET 03UF 17 PATENTEDIARZHUYE SHEET 08 0F 17 v iii PATENTEDHARZTISYS SHEET OSUF 17 PATENTEUHARZYISYB SHEET lEUF 17 PATENTEUHARZYISYS SHEET 13UF l7 PATENYEDHARZYISB 722 145 SHEET 1% BF 17 BACKGROUND OF THE INVENTION The present invention relates to a method of and to a machine for grinding, polishing or analogous treatment (hereinafter called grinding) of straight and/or curved surfaces on workpieces, especiallyon so-called turnplates. More particularly, the invention relates to improvements in automatic mechanical and/or electrolytic grinding of workpieces, especially to automatic grindin'g of large batches of identical workpieces normally consisting of hard metal. Such workpieces can be used as tools in machine tools for. removalof material from metallic or other blanks. Material removing tools which are employed in machine tools and like automatic or semiautomatic machines must be ground and/or polished at frequent intervals. Such treatment must be carried out with a high degree of precision and, at the present time, requires considerable amounts of time as well as the use of complicated machinery which must be serviced and supervised by skilled attendants.

SUMMARY OF THE INVENTION An object of the invention is to provide a novel and improved machine for grinding batches of metallic toolsand/or'other types of identical workpiecesin a fully automatic way, with substantial savings in time,

and with a high degree of precision.

Another object of the invention is to provide a machine according to which identical workpieces can be treated singly or in groups of two or more.

A further object of the invention is to provide a machine which is particularly suited for automatic treatment of so-called-turnplates which are used for removal of material in machinetools.

Still another object of the invention is to provide an apparatus wherein all operations can be programmed to insure rapid, economical and accurate treatment of successive workpieces and which can be rapidly con- I verted for treatment of different workpieces.

die-out feed and rapid retraction of workpieces to insure economical operation and satisfactory. finish of treated surfaces.

The'machine of the present invention is employed for mechanically and/0r electrolytically grinding flat and/or uneven (concave, convex or otherwise curved) surfaces on a succession of identical workpieces, particularly the surfaces of turnplates for use in machine toolsor the like. The machine provides ,the steps of mechanically moving at least one workpiece of the succession of identicalworkpiecds to a first predetermined position (e.g., by means of a pusher or the like which expels workpieces fromv a magazine), mechanically moving the workpiece from, such first position to a second predetermined position (for example, by means of a transfer device which comprises means for yieldably holding 'a workpiece during transfer),

mechanically clamping the workpiece in the second position (for example, between two clamping pins or the like), moving the thus clamped workpiece into engagement with the active surface of a grinding tool to remove material from at least one surface of the workpiece, disengaging the workpiece from the tool, and terminating the clamping action on the workpiece.

In accordance with another feature, the orientation of the workpiece is changed during transport from the first to second position; for example, the workpiece can be moved from a horizontal plane into a vertical plane in which it is in an optimum (second) position for engagement by the clamping pins. The orientation of the workpiece can also be changed after the workpiece assumes its second position; this can be achieved by resorting to templates or indexing means for one of the clamping pins. The workpiece may but need not rotate continuously during engagement with the active surface of the grinding tool, and the rate of feed as well as the maximum extent of movement of the workpiece against the tool can be varied in a fully automatic way by resorting to a suitable programming system.

The grinding tool preferably comprises a largediameter hollow cylindrical portion of considerable axial length having at one of its axial ends .a relatively narrow annular active surface.

The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The improved grinding machine itself, however, both as to its construction and its mode of operation, together with additional features and advantages thereof, will be best understood upon perusal of the following detailed description of certain specific embodiments with reference to the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING direction of arrows from the line IV-IV of FIG. 1 or 3 and illustrates the details of the clamping unit;

FIG. 5 is a fragmentary sectional view as seen in the direction of arrows from the line V-V of FIG. 4 and illustrates the means for adjusting the angular position of one of the clamping pins in the unit of FIG. 4;

FIG. 6 is an enlarged view of a detail in the structure of FIG.'4;

FIG. 7 is a fragmentary sectional view as seen in the direction of arrows from the line VIIVII of FIG. 4 and illustrates a portion of the means for moving the other clamping pin axially;

FIG. 8 is a fragmentary sectional view as seen in th direction of arrows from the line VIII-VIII of FIG. 4

FIG. 9 is a sectional view as seen in the direction of arrows from the line IX-IX of FIG. 8;

FIG. 10 is a plan viewof the magazine for workpieces and of a transfer unit which delivers workpieces from the magazine to the clamping unit of FIG. 4;

FIG. 11 is a vertical sectional view as seen in the direction of arrows from the line XI-XI of FIG.

FIG. 12 is a vertical sectional view as seen in the direction of arrows from the line XII-XII of FIG. 1 1',

FIG. 13 is a vertical sectional view as seen in the direction of arrows from the line XIII-XIII of FIG. 11;

FIG. 14 is a horizontal sectional view of the transfer unit;

FIG. 15 is a vertical sectional view as seen in the direction of arrows from the line XVXV of FIG. 14;

FIG. 16 is a sectional view as seen in the direction of arrows from the line XVI-XVI of FIG. 15;

FIG. 17 is a vertical sectional view as' seen in the direction of arrows from the line XVIIXVII of FIG. 4 and illustrates the means for controlling the movements of the carriage for the clamping unit;

, FIG. 18 is a sectional view as seen in the direction of arrows from the line XVIII-XVIII of FIG. 17;

FIG. 19 is a view of a detail as seen in the direction of arrow X in FIG. 17;

FIG. 20 is a side elevational and partly sectional view of the structure shown in FIG. 19;

FIG. 21 is an enlarged side elevational view of a receptacle in the transfer unit as seen in the direction of arrow Yin FIG. 14, a portion of the receptacle being shown in section;

FIG. 22 is a sectional view as seen in the direction of arrows from the lineXXII-XXII of FIG. 21;

FIG. 23 is an enlarged fragmentary sectional view as seen in the direction of arrows from the line XXIII- XXIII of FIG. 24 and illustrates an adjustable weight which moves the carriage for the clamping unit;

FIG. 24 is a sectional view as seen in the direction of arrows from the line XXIV-XXIV of FIG. 23; I FIG. 25 is a sectional view as seen in the direction of arrows from the'line Xxv-xxv of FIG. 24;

FIG. 26 isa view as seen in the direction of arrow Z in FIG. 25;

FIG. 27 is a sectional view as seen in the direction of arrows from the line XXVII XXVII of FIG. 26;

FIG. 28 is an enlarged vertical sectional view as seen i in the direction of arrows from the line-XXVllI--XX- VIII of FIG. 1 and illustrates the drive and theoscillating'means for the spindle of the grinding tool; V

7 FIG. 29, is a view substantially as seen in the direction of arrows from the line XXIX-XXIX of FIG. 28;

FIG. 30 is a front elevational view of a workpiece which can be treated in the machine of FIGS. 1 29;"

FIG. 31 is a side elevational view of the workpiece shown in FIG. 30; g

FIG. 32 is a front elevational view of a second workpiece;

FIG. 33 is a side elevational view of the workpiece shown in FIG. 32;

FIG. 34 is a plan view of an arrangement which is utilized to adjust the amplitude of oscillatory move 'ment of the carriage for the spindle'shown in FIGS. 28 and 29, with certain parts shown in section;

FIG. 35 is a view as seen in the direction of arrow XY shown in FIG. 34;

FIG. 38 isa sectional view as seen in ;the direction of arrows from the line XXXVIIIXXXVIII of FIG. 37;

and 1 FIG. 39 is a schematic plan view of a table for the structure shown in FIG. 4 and of means for changing the angular position of the table.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring first to FIGS. 30 and 31, there is shown a workpiece 1 which constitutes a turnplate and is of the type capable of being treated in the machine of the present invention, i.e., it can be subjected to an automatic electrolytic ormechanical grinding action. The workpiece l is of generally rectangular(square) outline and is provided with two phases or facets at each of its four corners. Each pair of facets includes a main facet 1b arid a secondary facet la. The four elongated side faces or end faces are shown at 1c and the two main surfaces are shown at 1d, 1e. Each main facet lb makes with the adjoining side face 1c an angle of 53 degrees and each secondary facet 1a makes with the adjoining side face 10 an angle of'l5. The plane of each main facet lb and each side face 10 makes with the symmetry axis of the workpiece 1 a positive angle 1 of 1 1. The angle between such symmetryaxis and the planes of the secondary facets 1a is 14. The two main surfaces 1d, 1e are at least substantially parallelto each other.

FIGS. 32 and 33 illustrate a workpiece or turnplate 2 of triangular outline. The corners of this workpiece are bounded by arcuate or negative facets 2a which are parallel to thesymmetry axis.

' A machine for automatic precision grinding is shown in FIGS. 1-29 and 34-39. This machine will be described with referenceto the treatment of workpieces 1 of the type shown in FIGS. 30 and 31. I I

Referring first to FIGS. 1, 2 and .10 to 12, the machine therein shown is designed for automatic electrolytic and/or mechanical grinding of workpieces having flat and/or curved surfaces. The machine comprises a magazine 3 which .can accommodate a supply of stacked workpieces 1, and a withdrawing device or pusher 4 which can remove from the lower or discharge end'of the magazine 3 one or more workpieces at a time. The pusher 4 is arranged to move back and forth in a substantially horizontal plane and delivers workpieces to a transfer unit 5 which is designed to move the thus received workpiece or workpieces in a direction at right angles to the direction of movement of the pusher and into a clamping or gripping unit 6 which then assumes a predetermined receiving or accepting position. The clamping unit 6 is shown in FIG. 4 A.workpiece 1 which is about to be received by the clamping unit 6 is located in a vertical plane. The elements of the clamping unit 6 engage the main surfaces 1d, le'of the freshly transferred workpiece 1 and are indexible to change the orientation of the workpiece so as to place selected facets and/or faces of the workpiece into an optimum position for removal of material by a grinding tool 7 here shown as a cupped wheel. In addition to being .indexible, the elements of the clamping unit 6 are preferably also capable of performing a rotary movement to thereby move selected arcuate facets or faces of a workpiece (e.g., the arcuate facets 2a of the work- 

1. In a machine for grinding of a succession of identical workpieces, a combination comprising a magazine arranged to contain a supply of workpieces and having an outlet for workpieces; a withdrawing device operative to evacuate through said outlet at least one workpiece at a time and to advance such workpiece along a predetermined path; a transfer unit including a receptacle movable between a first position in which it receives the workpiece from said withdrawing device and a second position, and means for moving said receptacle between such positions; a clamping unit including two coaxial clamping members movable together to and from a receiving position in which they flank a workpiece in said receptacle in the second position thereof, means for moving one of said clamping members toward and away from the other clamping member to respectively grip and release the workpiece therebetween, and a carriage for moving said clamping members to and from said recEiving position; and a grinding tool positioned to remove, in response to movement of said carriage, material from a workpiece which is gripped by said clamping members.
 2. The machine as defined in claim 1, wherein said withdrawing means comprises a reciprocable pusher and the means for moving said receptacle comprises double-acting fluid-operated cylinder means, said carriage being arranged to move at right angles to the common axis of said clamping members and said tool comprising a rotary grinding wheel.
 3. The machine as defined in claim 2, further comprising a common support for said magazine, said carriage, said transfer unit, said withdrawing means and said tool.
 4. The machine as defined in claim 1, wherein said withdrawing means includes a reciprocable pusher and further comprising means for reciprocating said pusher including a platen secured to said pusher, a double-acting cylinder having a piston rod including a portion extending through and beyond said platen, and resilient means bearing against said portion of said piston rod and reacting against said platen to thereby tend to move said piston rod outwardly, said pusher being arranged to evacuate workpieces in response to retraction of said piston rod into said cylinder.
 5. The machine as defined in claim 4, further comprising a platform adjacent to said path intermediate said outlet and said receptacle in the first position thereof to support articles which move along said path, and means for moving said platform with said pusher including an actuating rod operatively connected with said platform and arranged to share a portion of movement of said platen in response to retraction of said piston rod.
 6. The machine as defined in claim 5, further comprising second resilient means arranged to oppose movement of said platform with said platen with a force which is weaker than the force of said first-mentioned resilient means.
 7. The machine as defined in claim 1, further comprising means for adjusting the level of said withdrawing device.
 8. The machine as defined in claim 1, further comprising a back support for said receptacle in the first position thereof.
 9. The machine as defined in claim 1, wherein said receptacle is provided with a recess for workpieces and with locating surfaces bounding said recess, said transfer unit further comprising a pair of retaining jaws flanking said recess and movable in planes disposed at right angles to said locating surfaces.
 10. The machine as defined in claim 9, wherein at least one of said jaws is provided with detent means for yieldably retaining workpieces in said recess.
 11. The machine as defined in claim 1, further comprising means for changing the orientation of said receptacle in response to movement between said first and second positions.
 12. The machine as defined in claim 11, wherein the means for moving said receptacle comprises a double-acting cylinder having a reciprocable piston rod connected with said receptacle and said means for changing the orientation of said receptacle comprises a cam and a follower secured to said piston rod and arranged to track said cam.
 13. The machine as defined in claim 1, further comprising means for moving said transfer unit up and down.
 14. The machine as defined in claim 13, wherein said means for moving the receptacle between said first and second positions comprises a double-acting cylinder and the means for moving said transfer unit comprises a reciprocable second carriage for said cylinder, and further comprising adjustable means for limiting the extent of movement of said second carriage.
 15. The machine as defined in claim 1, wherein the means for moving said one clamping member comprises an axially reciprocable shaft coaxial with and rotatably supporting said one clamping member, a pivotably mounted lever having a shorter first arm coupled to said shaft and a longer second arm, and double-acting clamping cylinder means for pivoting said lever by way Of said second arm.
 16. The machine as defined in claim 15, further comprising a bearing member pivotally supporting said lever for movement about an axis which is normal to the axis of said shaft and a pull rod secured to said carriage and supporting said bearing member, said pull rod being parallel to said shaft and said cylinder means.
 17. The machine as defined in claim 1, wherein said clamping unit further comprises a shaft fixedly secured to and coaxial with said other clamping member, and means for changing the angular position of said shaft.
 18. The machine as defined in claim 17, wherein the means for changing the angular position of said shaft comprises a worm wheel rotatably mounted on said shaft, a motor-driven worm meshing with said worm wheel, and electromagnetic clutch means energizable to couple said worm wheel to said shaft.
 19. The machine as defined in claim 18, further comprising means for selecting the extent of angular movement of said shaft.
 20. The machine as defined in claim 1, further comprising a support for said carriage and means for moving said carriage in a direction to advance a workpiece which is gripped by said clamping members into engagement with said tool, including a weight attached to said carriage.
 21. The machine as defined in claim 20, further comprising double-acting cylinder means for controlling the speed of movement of said carriage under the action of said weight and for moving the carriage in a direction to disengage the workpiece from the tool.
 22. The machine as defined in claim 21, wherein said cylinder means is arranged to move said carriage against the opposition of said weight to a starting position and further comprising elastic cushions arranged to store energy in response to movement of said carriage to such starting position.
 23. The machine as defined in claim 21, further comprising means for controlling the operation of said cylinder means so as to effect rapid advance of said carriage between said starting and receiving positions and from said receiving position in a direction to move a workpiece between said clamping members toward said tool, and to effect a relatively slow advance of said carriage in said direction to move the workpiece into engagement with the tool.
 24. The machine as defined in claim 1, further comprising adjustable stop means for limiting the extent of movement of said carriage in a direction to feed a workpiece between said clamping members during engagement with said tool.
 25. The machine as defined in claim 24, wherein said stop means comprises a template connected to and angularly movable with one of said clamping members and a ruler constituting an abutment for said template.
 26. The machine as defined in claim 24, wherein said stop means comprises an indexible cam.
 27. The machine as defined in claim 26, further comprising a support for said carriage, said cam being indexible with reference to said support and having a plurality of lobes of different height, said carriage comprising a projection which registers with a selected one of said lobes and terminates the feed movement of said carriage in response to engagement with such selected lobe.
 28. The machine as defined in claim 27, further comprising means for signaling the positions of said cam.
 29. The machine as defined in claim 27, further comprising means for indexing said cam.
 30. The machine as defined in claim 29, wherein said means for indexing comprises a pinion, one-way clutch means coupling said cam to said pinion, a rack meshing with said pinion, and means for moving said rack.
 31. The machine as defined in claim 27, wherein said projection is adjustable with reference to said carriage and further comprising means for effecting precise adjustments in the position of said projection.
 32. The machine as defined in claim 27, further comprising pressure gauge means associated with said projection to produce signals in response to a predEtermined pressure between said projection and the selected lobe of said cam.
 33. The machine as defined in claim 1, further comprising a support for said carriage, means for moving said carriage with reference to said support between a plurality of positions including said receiving position and a starting position, and adjustable stop means for arresting the carriage in said starting position.
 34. The machine as defined in claim 1, wherein said tool comprises a rotary cupped grinding wheel arranged to accommodate a portion of said carriage during removal of material from a workpiece between said clamping members.
 35. The machine as defined in claim 1, wherein at least a portion of said means for moving said one clamping member consists of current-conducting material.
 36. The machine as defined in claim 35, wherein said current-conducting portion includes a rotary shaft and is provided with at least one sliding contact, and further comprising collector means disconnected from said sliding contact in response to rotation of said shaft.
 37. The machine as defined in claim 36, further comprising elastic current-conducting coupling means connecting said collector means with a portion of said shaft.
 38. The machine as defined in claim 1, further comprising a support for said carriage and means for moving said carriage with reference to said support including a cable connected with said carriage, a plurality of weights, and means for suspending a selected number of said weights on said cable.
 39. The machine as defined in claim 38, wherein said last-mentioned means comprises a turntable and intercepting members articulately connected with said turntable to intercept some of said weights in one position of said turntable and to permit all of said weights to act on said cable in another position of said turntable.
 40. The machine as defined in claim 1, further comprising a frame, a support for said carriage, said support being turnably mounted in said frame, means for changing the angular position of said support, means for limiting the extent of angular movement of said support, and means for holding the support in selected angular position.
 41. The machine as defined in claim 1, wherein said grinding tool comprises a large-diameter hollow cylindrical portion of substantial axial length, said cylindrical portion having a narrow annular active surface in the region of one axial end thereof. 